Super hydrophobic surface fabrication method

Abstract

The present invention relates to a method for producing a super-hydrophobic surface, and to a stack having a super-hydrophobic surface prepared by the above method. The super-hydrophobic surface may be realized only by plasma etching and deposition. The super-hydrophobic surface according to the present invention has a very low work of adhesion less than or equal to 3 mJ/m 2 . This super-hydrophobic surface may be applied to various fields including self-cleaning surface, anti-fogging surface, automobile glass surface, and drug delivery device surface.

1 . A method for forming a super-hydrophobic surface, the method comprising:
 a) preparing a substrate having a mask disposed thereon, wherein the mask has a two-dimensional pattern in which holes having a micrometer scale are arranged at regular intervals;   b) treating said substrate having the mask with a plasma of a fluorocarbon containing gas such that a fluorocarbon layer is formed on inner faces of the holes of the mask;   c) treating said substrate having the mask with a plasma capable of etching the fluorocarbon layer and the substrate such that vertical rods corresponding to the pattern of the mask are formed on the substrate;   d) repeating the steps (b) and (c) to increase height of the vertical rods; and   e) after the step (d), treating the substrate having the vertical rods formed thereon with a plasma of a fluorocarbon containing gas to form a fluorocarbon layer on outer faces of the vertically rods.   
     
     
         2 . The method of  claim 1 , further comprising:
 a step of plasma ashing and a step of removing the mask, which are performed between the step (d) and the step (e).   
     
     
         3 . The method of  claim 1 , wherein the step (d) are repeated 5 to 500 times. 
     
     
         4 . The method of  claim 1 , wherein the fluorocarbon containing gas is at least one selected from a group consisting of C 4 F 8 , C 4 F 6 , C 2 F 6 , CF 4 , and CH 2 F 2 . 
     
     
         5 . A stack structure having a super-hydrophobic surface, wherein the stack structure comprises:
 a substrate; and   a plurality of vertically oriented rods formed on the substrate, wherein the rods are formed by the method of  claim 1 , wherein the plurality of vertically oriented rods are arranged in a two-dimensional pattern at regular intervals, wherein each of the rods has a diameter equal to or smaller than 4 micrometer.   
     
     
         6 . The stack structure of  claim 5 , wherein the super-hydrophobic surface has a contact-angle equal to or larger than 160°. 
     
     
         7 . The stack structure of  claim 5 , wherein the super-hydrophobic surface has a work of adhesion equal to or smaller than 3 mJ/m 2 . 
     
     
         8 . A stack structure having a super-hydrophobic surface, wherein the stack includes:
 a substrate; and   a plurality of vertically oriented rods formed on the substrate, wherein the rods are formed by the method of  claim 1 , wherein the plurality of vertically oriented rods are arranged in a two-dimensional pattern at regular intervals, wherein each of the rods has a diameter equal to or smaller than 10 micrometer, wherein a height of each of the rods is equal to or larger than 7 micrometer.   
     
     
         9 . The stack of  claim 8 , wherein the super-hydrophobic surface has a contact-angle equal to or larger than 160°. 
     
     
         10 . The stack of  claim 8 , wherein the super-hydrophobic surface has a work of adhesion equal to or smaller than 3 mJ/m 2 .